Engine starter gearing



1 1959 e. $.SPENCER 2,872,823

ENGINE STARTER GEARING Filed Aug. 30, 1957 INVENTOR.

.TTORNEY nited States Aviation Corporation, Elmira Heights, N. Y., a corporation of Delaware Application August 30, 1957, SerialNo. 681,260

4 Claims. (Cl. 74-6) The present invention relates to engine starter gearing of the mechanically shifting type, and more particularly to means embodied in the shifting mechanism for rotating the motor pinion slightly as it is moved into mesh with the engine gear, to facilitate such mesh.

In those types of starter gear shifts in which the motor driven pinion is moved axially into mesh with an engine gear by a pivoted fork lever which is manually or electromagneticaly actuated, it is customary to energize the starting motor by a switch which is closed by the final meshing movement of the shifting lever. In such systems, a mesh-enforcing spring is usually interposed in the shifting connection which yields in case of failure of the pinion to properly enter into mesh with the engine gear, thereby permitting the shifting lever to complete its travel so as to close the'starting motor switch. The motor thereupon rotates the pinion from its abutting relation with the engine gear, and the expansion ofthe mesh-enforcing spring then moves the pinion into mesh with the engine gear. An example of this type of shift is the patent to Miller 2,593,167 issued April 15, 1952. V

In order to secure proper mesh ,of the pinion after tooth abutment has been overcome in this manner, it is necessary for the mesh-enforcing spring to be powerful enough to snap the pinion into mesh very quickly, other wise the pinion will simply mill off the teeth of the engine gear Without rotating it. This requirement is especially drastic in the highvoltage systems using motors with very high stall torque and rapid acceleration characteristics. The compression of such a mesh-enforcing spring entails much exertion on the part of the operator, or a large and expensive solenoid if the shift is operated electro-magnetically.

It is an object of the present invention to provide a novel starter gear shift which is. positive and reliable in operation, simple in construction and economical to manufacture.

It is another object to provide such a device incorporating means other than the starting motor for indexing the motor driven pinion out of abutting relation with the engine gear.

It is another object to provide such a device in which the necessity for a stiff mesh-enforcing spring is eliminated.

It is another object to provide such a device having means for preventing closure of the starting motor switch until after the pinion is meshed with the engine gear.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing in which:

Fig. 1 is a side elevation, partly broken away and in section, of a portion of the starting motor with the gearing mounted thereon and the shifting mechanism formed in accordance with the present invention;

Fig. 2 is a section taken substantially on the line 22 of Fig. 1;

Fig. 3 is an enlarged sectional detail of the shifting collar and its mount on the shifting sleeve;

atent O 2,872,823 Patented Feh. 10, 1959 Fig. 4 is a detail showing a form of overrunning connection between the shifting lever and shifting collar which is different from that shown in Fig.1;

Fig. 5 is a section taken substantially on the line 5-5 of Fig. 4; and v Fig. 6 is a detail similar to Fig. 4 showing a third form of said overrunning connection.

In Fig. 1 of the drawing there is illustrated a starting motor 1 having an extended armature shaft 2 which is supported on an outboard bearing 3 provided in a housing 4 attached to the motor frame in any suitable manner. A pinion 5 is slidably journalled on the motor shaft 2 for movement into and out of mesh with a gear 6 of the engine to be started.

A shifting sleeve 7 is splined on the armature shaft as indicated at 8. The sleeve 7 is provided with inclined driving projections 9 adapted to engage similar projections 11 on an intermediate coupling member 12. Conpling member 12 is provided with overrunning clutch teeth 13 normally meshing with similar clutch teeth 14 on a flange member 15 fixed to the pinion. A barrel member 16 limits separation of the flange 15 of the pinion from the sleeve 7, and a spring 17 in the barrel 16 bearing against a flange 10 on coupling member 12 normally maintains the overrunning clutch teeth 13, 14 in engagement. This structure accordingly provides a swivel connection from the sleeve 7 to the pinion 5 incorporating a self-tightening overrunning clutch.

Means for moving the sleeve 7 to slide the pinion 5 into and out of mesh with the engine gear 6 is provided comprising a forked lever 18 pivoted on the housing 4 as indicated at 19 and arranged to be actuated through suitable linkage attached to its free end, either manually or electro-magnetically. The forked end 21 of the lever 18 carries on its tines 22, 23 (Fig. 2) a pair of blocks 24,

25 having a sliding bearing in a channel formed by spaced flanges 26, 27 on a shift collar 28. Collar 28 is splined as indicated at 29 (Fig. 3) on a bushing 31, being retained thereon by a lock ring 32. A spring 33 seated against a flange 34 on the end of bushing 31 urges the collar 28 against said lock ring.

Bushing 31 is rotatably mounted on a reduced portion 35 of the shifting sleeve 7 and is frictionally connected therewith by means of a rippled spring washer 36 which seats against a shoulder 37 on the sleeve 7 and presses the bushing 31 against a lock ring 38.

A motor switch 39 having a plunger 41 is arranged to be closed by a cap screw 42 mounted on the lever 18 and adjusted to close the switch when the lever has completed its shifting movement and thereby brought the pinion 5 into mesh with the engine gear 6.

Means are provided for utilizing the vertical movement of the blocks 24, 25 as the shifting fork traverses its arcuate path, in order to rotate the shifting sleeve 7 slightly in a forward direction to thereby index the pinion 5 on the armature shaft. For this purpose as shown in Figs. 1

and 2, the blocks 24, 25 are provided with expansive spring clutch members 43, 44 which bear against the flanges 26, 27 of the collar 28, the ends of said clutch members being so curved that they will expand and grip said flanges when the block 24 is moving downwardly and when the block 25 is moving upward. Since the forward direction of the shaft 2 is in the direction of the arrow in Fig. 2, the clutch members 43, 44 are effective to rotate the sleeve 7 and consequently pinion 5 in a forward direction.

In operation, starting with the parts in the positions illustrated in Fig. 1, movement of the forked lever 18 in a counter-clockwise direction by the usual linkage will shift the collar, sleeve and pinion assembly to the right, and if the pinion teeth mesh properly with the tooth spaces of the engine gear 6, the pinion will be moved into full mesh as shown by the dotted lines in Fig. 1, and

the starting switch 39 will be closed by the cap screw 42 causing the engine to be cranked.

If however during the meshing movement, a tooth of the pinion should abut against a tooth of the engine gear 6, the meshing movement of the sleeve 7 and bushing 31 is arrested.'. A limited amount of further movement of the collar 28 and lever 18 is permitted by the spring 33, and during this movement the clutch, 44 continues to rotate the collar 28 slightly, which rotation is transmitted through the splined connection 29 to bushing 31 and through the frictional connection of the bushing to the sleeve 7 and consequently through the overrunning clutch teeth 13, 14 to the pinion 5. If this indexing movement of the pinion is suflicient to relieve the abutment against the engine gear, the meshing movement of the pinion will then proceed as usual. If this indexing movementis not suflicient to relieve the abutment however the movement of the lever 18 is arrested by the flange 34 engaging the collar 28 so that the motor switch 39 is prevented from closure. In such case, the operator allows the lever 18 to return to normal position, and then repeats the actuation of the lever to mesh the pinion. Since the pinion is indexed in a forward direction by this oscillation of the lever 18, it will be moved away from its abutting position, thereby securing proper meshing relation with the engine gear.

In Fig. 4 there is illustrated an alternative form of overrunning clutch between a block 25 and the flanges 26, 27 of the collar 28. In this form, the clutch comprises a ball or roller member 45' seated in a tapered channel 46 in the block 25 and urged by a spring 4'7 toward the shallower part of said channel.

In Fig. 6 a similar function is performed by a wedging lever 48 pivoted by means of a pin 49 on the end of a tine 22 of the forked lever 3.8, the wedging lever 38 being designed to engage between the flanges 26, 27 of collar 28 and transmit forward rotation thereto while permitting overrunning. A spring 51 urges the wedging lever 48 against said flanges.

It will be understood that the frictional connection between the bushing 31 and the sleeve 7 is arranged to yield on overload such as might occur in case of backfire of the engine causing backward rotation of the motor shaft while the pinion 5 remains in mesh with the engine gear 6.

Although certain structure has been shown and described in detail it will be understood that changes may be made in the design and arrangement of the parts without departing from the spirit of the invention.

I claim:

1. In starter gearing for internal combustion engines a motor shaft, a pinion slidably journalled thereon for movement into and out of mesh with a gear of the engine to be started, a sleeve splined on the motor shaft, a swivel and overrunning clutch connection from the sleeve to the pinion, a flanged collar mounted on the sleeve, means transmitting rotary and axial movement of the collar to the sleeve, a pivoted forked lever having tines engaging said collar, and means on at least one of said tines for rotating the collar while shifting the collar axially; in which the means for rotating the collar comprises an overrunning clutch connection from said tine of the forked lever to the collar.

2. In starter gearing for internal combustion engines a motor shaft, a pinion slidably journalled thereon for movement into and out of mesh with a gear of the engine to be started, a sleeve splined on the motor shaft, a swivel and overrunning clutch connection from the sleeve to the pinion, a flanged collar mounted on the sleeve, means transmitting rotary and axial movement of the collar to the sleeve, a pivoted forked lever having tines engaging said collar, and means on at least one of said tines for rotating the collar while shifting the collar axially; in which the means for transmitting axial movement of the collar to the sleeve includes a yielding connection from the collar to the sleeve permitting a limited travel of the collar in the meshing direction after meshing movement of the sleeve has been prematurely arrested, and a positive connection which prevents completion of the stroke of the forked lever until the pinion has meshed with the engine gear.

3. Engine starter gearing as set forth in claim 1 in which the means for transmitting rotation from the collar to the sleeve includes a frictional connection arranged to slip on overload.

4. Engine starter gearing including a motor shaft, a pinion slidably and rotatably mounted thereon, a sleeve splined on said shaft, a swivel and overrunning clutch connection from the sleeve to the pinion, a bushing swivelled on the sleeve and having a frictional rotary connection therewith, a collar splined on the bushing having spaced radial flanges, yielding means for transmitting axial movement of the collar to the bushing, a pivoted forked lever having its tines extending between the flanges of the collar, and overrunning clutch connections from said tines to the collar for rotating the collar while shifting it axially.

References Cited in the file of this patent UNITED STATES PATENTS 1,651,127 Jackson Nov. 29, 1927 1,974,985 Cunnius Sept. 25, 1934 1,995,765 Carle Mar. 26, 1935 FOREIGN PATENTS 815,277 Germany Oct. 1, 1951 

